Sylvestek s



May 1, 1923.

. 5. MCGRATH ROTARY KILN Filed March 50. 1921 www lllllllll lllllllltl UNITED Si? Application hier?, tlarch 3U, i921..

To all fw from t may concern.'

Be it known that I, SrLvns'rnn S. Mo @nari-r, a citizen ot the United States, re siding at lest New Brighton, borough ot Richmond, in the county oit Richmond and State oi, New Yorlr, have invented a certain new and useful Rotary Kiln, of which the following is a specification.

rlhis invention relates to rotary lrilns for roasting, calcininr; limes and plasters or for other analogous uses, hut is particularly adapted for the production ot hydraulic or Portland cement clinlrer.

According to the best authorities, hydrau lic or Portland cement is the product ohtained hy an intimate and properly proper tioned iniXture of argillaceous and calcareous materials, which produces a clinlrer when calcined to incipient fusion, and there calcination should cease, and .the clinlrered product reinoved as soon as possible.

The general method new used 'tor producing' hydraulic cement clinlrer is to pass a mixture of materials to he calcined through long rotating' refractory lined metallic cylinders or horizontal tubular kilns oft uniform interior diameter throughout their entire length. These kilns, are, in practice, sligzjhtl)T inclined and are mounted on trun nions for rotation h v any suitable power. A hood, provided with a discharge opening, is associated with the lower end ot the lriln and within the hood is positioned burning apparatus adapted to inject a tlanie into the kiln to act upon the material passing therethrough. The upper end ot the lriln is provided with a stack to allow et the escape ott the ,frases produced hy combustion and chemical decomposition andnieans is also associated with the upper end o'l" the kiln Alor supplying a mixture or materials to he calcined, or clinkered to the retort.

In the well known process of in airing hy* draulic cement, the unhurnt material is ted into the upper end or a rotary lrilu oi the character specified, its upper cud. il travels along the inclined invert ot the reifractory lined tubular kiln, in a thiclt layer, which is continually' turned over hv the rotary motion ot the kiln, and is dried, and the dioxid gases driven oli", as the heat troni the lower end comes in Contact with it, this in the drying or low temperature come,

As thel material progresses, it enters the Bultex-ing or calcmmg zone, where the heat i un. Maese.

sonic degrees higher, and which causes the particles oi pulverulent materials, to collect and form a viscous niass, which has a tendencyV to adhere, and accumulate upon the ot the kiln and torrns an obstruction. or rino toi-mation, which cholcs up the lriln, aud retards the progress of the materiels, :is they leave the sintering,r and enter the hurninp; zone, and at this point hecoiue an .incandescent inass, which as it tolls into the 'burning lcone, or highest teinpereiure roue, has a tciidencj;7 to become overliurht. Vll`he ring; -formation also has a teudene;Y to injure t e refractory lining of the hihi. and cause it to spall and tall out ot place, und when it loeconies so large, as to alniost stop all further progress of the mr vials. the kiln niust he stopped in its operation.A and allowed to become cooled, and the obstruction or ringr Ltorniation, removed liv manual lahor.

lilith the iloreo'oinp; considerations in mind, the ohiect ott the present invention is to provide e. kiln ot the character speciiied, which will he more etlicient, economical, re liahle and rapid in its operation ott producirre` (ornent clinlrer and ltilus olb the construe" tion speciiied, and which may he operated with greater capacita7 than kilns of the char roter referred, ton

.":ei'rjvluo out the present invention in ed tortue, the lriln is con strut-tod tl orin ot :i rotating; cjviindrical -dru'ro provided with a refractory iiiiorf. iho hilo iff mounted For rotation on an inclined mit: and associated with its opiiiosilc ends :irc a hood and steelt as heretofore. llrirecul is i Cfociated with the stach end ot the hihi introducinnn material into the hihi and hurner associ ated with the hood or lower end o? the kiln. During the operation ot the hihi. the interior oi is theoretically divided i. namely'. :i drying' Zone ad- ,Y end ot the hihi, an

o eine or sii'iterins acne, and a .f cliolrerinn zone. which occupies c or outlet end oi' the lqiiln. The

liiln is so constructed 'that it is of substan` tisillv the same cross sectional area tor the {ri-coter portion on its lourfth and through that perl' ot the lrilu co:istitutinnm the dry and calcini while the portion tutes' thel .hurning an interior contifru one oi" its pre ration substantially in the form of a truncated cone. In other words, the inner surface of the kiln at the exit end thereof verges from theadjacent calcining zone with a pronounced taper, so that the o utlet end of the kiln, constituting the burnin zone, flares outwardly to an increased diameter atiits outlet end. As a result of this construction, the unhurnt materials in passing through the drying zone and into and through the calcining zone, which zones are of uniform diameter,come to a-point of calcination and incipient fusion 1n the 'burning zone. and starts to accumulate and torni clinker balls at aboutthe time the ma te'rial advances well into the burning zone. "As the :mate-rial passes into the burning zione and proceeds to-'form into clinker balls, it simultaneously passes from the relatively restricted cross sectional area of the .calc'i'ning zone into the gradually enlarging or ldiverging space Within `the 'burning zone. `Since'the path of'travel of the. burning materialis constantly enlarging as the material proceeds, this Vrapidity of flow of `movement willincrease and there will therefutter he less opportunity for the viscous mass of material to adhere to the sides of the lkiln and choke the bore thereof. As the uewltY fornied calcined product falls forlward. or rolls into 'the gradually enlarging and revolving greater space, it takes on a-'t'an shape-form or mass upon the invertof the-truncated cone shaped burning'zone.` where the yflame of the burning 'apparatus -inujiinges directlvupon the rapidly moi Vino-*mass of materialy at apoint' on the in vert immediately forward land below'the outlet of the calcining Zone. By providing' the tapering or diverging walls in the hurning zone, I am enabled to effect a great economy lof fuel, as less heat units are required' to calcine cement lmakingmaterial and cause it to clinker when the flame impinges directly upon a moving mass of material as'it passes through the burning Zone.

Another feature of the invention consists in providing a retort of the character speciliedl wherein the refractory liningof the burning zone is ina-de thicker and heavier vthan vthe other zones, so as to withstand the heat required for the `burning operation at this point-while noty unduly increasing the lweight of the-kiln other points which are required to withstand a lower temperature of heat.

Features ofthe invention. other? than those-specified.Hwill, befapparent from' the heifeinafterfdetailed description and claims. when read 1n Yconpinction `with the accom- -pitnvingv drawings.

,Thef accompanying drawingsy .illustratel is to he understood as illustrative, only, and not as defining the limits of the invention.

Figure l is a side elevation of a kiln enibodving the present invention.

Figure 2 is a central section through thc rotary kiln portion of the kiln.

'Figure 2l is a section on the line 3 3 of Fi ure 2; and.

*igure 4 is a section on the line 4--1 of Figure 2.

In the accompanying drawiu thc kiln is` shown in the form ot a shell l. which, in practice, may vhe constructed in any desiredy manner. such as hy huilding up the kiln ot' metallic sections and providing the saine with a refractory lining 2. The kiln 1s mounted vfor rotation on an inclined axis yon a plurality of rollers 3. supported on suitable pillows 4 and operating upon bands secured circumferentially of the kiln. In practice, rotation may be couvenientlv imparted to the kiln hy associating an annular gear with one of the hands 5 and driving such gear from any suitable power mechanism.

Associated with the upper or inlet end of the kiln is a housing T into which the products ot combustion and gases due to cheniical decomposition flow 'from the kiln dui'- ing the operation thereof and may he lead ott' through tht` stack 8. Suitable feed mechanism 9 is also associated with the inlet end ot-the kiln and serres to introduce the material to he operated upon into said kiln.

The 'lower end ot' the kiln has associated therewith a hood lll providingr an outlet pas sage ll for the treated materials and with which hood is associated burning apparatus 12. The hood may he of any conventional kind and may be associated with the kiln in `any.well'knovii'n desired way. 'The hood per se forms no part of the present invention. nor does the feeding mechanism. outlet chamber 7 or the stack 8.

`The invention as-hcreinhefore stated is directed to thev kilnand its lining and has more particularlv to do with the shaping of the kiln in the manner next tohe described.

`When the kiln is operated' tofprodnce'ce ment clinker, the interior ofthe kiln theoreticallrdivides itsinto three distinct zones. namely. the-drying zone. the calcining zone and tliefluirnine4 zone. through which zones material successively passes during its travel fromv the inlet to 'the outlet end of the kiln.

Material is fed into the upper `end of the lkiln through the feeding mechanism 9 and is caused to roll and fall dnwn'the kilndiv the revolving of the lattzer. During its pas sagethrough the retort. suchNmterial is heatedhv. any of theusual methodsgfprefer- Iahlyby injecting gasoil orupowdered coal f-thiiough thefpipe .12 into the. kiln indernir pressure and causing such fuel to" hui'n in llll thi

gee oi heut withiiu the hihi and Sei-ves mei-ely to dry the meteifmi ne it passes; 'Loi' poi'tiou ot the lenggjti'i oit the i5 through. the celled drying; zone. ioetei'izil pi'oCee-Cie the heeft becoi'iies higijhei eind continues to ioci'eziee ie the metoiioi @aegee through ti'ie ezilciiing Zone "Whei'e ,it ie biou 1 to o, gioiut et culeihetion, eo that by the time it leaves the oeleihiiig Hohe. abri, e'oteiffg; the buitliufi' Lione, it ie in zi couditioh to be dheoth u, upon by the thime '1.93% tiehei'oi'med into si, viecoue cheiecteif mui fused oi; burnt thioufzjh the direct action ot the l2 thereon.

u kih heretofore ueech inveiizibiy been eonetueteci 'with lmi'feiim interior diem/atei throuo'hout theii1 ier" h and when thus toi-mech it ie tom l 'thi` et the point Where the umteifizi'i be fie to pei?- tebe ot the viscous form, euch meteiiizii tende to etici?, or adhere to the weil et the hihi und iu time causo :i rim); or eimuhii beiliei' to collect et e point just beyond the fiume.

ti e hihi coutiiiuee to oih-iete the me.- teiiiil heini beek by the .ifu

euch khle time ,toi i and choked so that it becomes; heceeemy to remove the time; bottom the hihi @am progieiijf function. Thie iieceeeitetes the etoppiw ot the iippol'etue, the peirmittiufej of it to et: idie to? Some time Wifiiie it oo, imi foi-- vittel' Woii'hiuieh me ee1 into the k. `u to Chop out the ring; thus; "formed, Y

Iii th@ pieeerit inventionn ,i enti i overcome thie dieedwmtzipje und ins-idem Weete in time zuid hiboi' by forming the 'iowei utlet end ot the hihi of fiueto ooiiicei, ehehe which ehepe is extended along the hihi` eo es to preteifebbjif enclose the eiitii'e biiifiiiutf zone omi. slightly beyond the Seme. This portion oit the klhi ie designated by the "freteience character 1li en@ it will eppefii lii'om. the drawings that it extends 'vom the oeh cininpj eolie iii with timing oir (iii/'erging ellerto the tower? miti of the hilo To bww? tice. t pi' teiobl boifide this iiffiusto conica? oi? tapered portion of the hihi with :i fifectoi'jf meteiiial fl, which? sie showin ie thicker theb the huioge: it thifou f hoiit the Ve iiiei'edei of the hiln :and it et thie heft oi" the hihi thrit the pjieeteet heet ie bi That mit ot the hihi between the ohm? end envi the tiueto comic-ei, tebeieo po' 1f; is pifeteiebly mede ot u iLtoim iuteiioi" diameter @tem-ty ehowu in Figure ot the (hem/inge.

The 'formation of the hihi with :i epei buicniug; zone of eubetentieliy tiuete conical cheifectei described, und the eppiicetou of the burning thune l2, eo that it will im-` piego the tapering@ well ot such burning mono7 constitute the essence of this inventioo, e' thiougjjh the iucolpoiatioo of these ituiee iu kiln construction, the kiln emibieii to 'tuuctioii mote efficiently and.

uigoii the ihmbui'biiio zone. ufheie the @eine i humm L apparatus meme-ee (hi-wily i on be me mafie ot ibrfxtoviei nini Het a i of 'fu-lion o? the eeuw. i-iu'uul oi'wifiti the wpeiof; elle of the hul :como t: fifi the unies of mritei'ie'i iii uiotiob` ont it cannot come to met :imi milwi'e to iiiiioloj ot the hihi, Titou-emilia es the we@ ot iuoveineiit of? the iimteiiei ie i11- oifezisifm hoi Sie om@ "a through the burni Liuc? Pimm ew ie iio teudeiiit' ot the iiiet it up eufi 'ioim e time' :is hei'eiuu Vi mmf be to@ the ei we been poes' Y Y toe diicifeuef portion E ot the iuiiigij, it ie ieee liable to iiijui'e the hiiihgg; or ehh. time though e thin hhigogf were pvmfided throughout the entire hihi. Accoiffhimby, the t me may unbiuge the iinir without Fiemme the immo :1mi thus euebiee the metoiiei to bo move@ tnetei ighi'ough the hihi eiuco si, ojifesitei' i'ioet may o@ *plied ie, the bowing; zone. it ie toned by `uioviuo the hmtm'iei through tho hihi moie mpioijv than iieietotoi'eN the cepioitjr of' the ziipoaetue is not oobf iu- `oioeiwitefi upon both 'toi' toet emi eouiifhieeae Llllo ywhat I claim as new and desire to secure by ing an inclined kiln mounted for rfration,

said kiln being cylindrical and of a uniform interior diameter for the major portion of its length lfrom the feed end thereof and the remainder of its length being of circular frusto conical shape direi-ging toward the disehar e end of the kiln which is unobstructe so thaty material traveling down the frusto conical portion of the kiln will not be arrested ybut flow freely from the disf charge end thereof, and a lining for the kiln, said lining being of greater ickuess within the frusto conical portion of thc kiln than Within the cylindrical poi-tion o the kiln.

3. A cement burning apparatus lndiotlying a tubular kiln mounted for rotation on an inclined axis and having an uno'f dischar e end, said kiln being of un i terior iameter for the greater poitou ot its vlength from the charfring end of the kiln, so that material will travel through such portion at a relatively slow speed, and the kiln being frusto conical for the remainder of its length so that the material upon entering the frusto conical ortion will in crease in speed of travel am be unobstruct-A edly discharged from the discharge end thereof.

4. A cement burning apparatus embodying a tubular kiln mounted for rotation on an inclined axis and having an unobstructed discharge end, said kiln being of uniform interior diameter for the greater portion of its length from the charging end ot the kiln, so that material will travel through such portion at a relatively slow speed, and said kiln being frusto conical tor the remainder of its length so that the material, upon entering the frusto conical portion. will increase in speed ot travel and be nuobstructedly discharged from thc di a:har, r,l end thereof, and a refractory lining within the kiln.

5. A cement burning apparatus embodying a rotating refractory lined metal tubu lar kiln mounted to rotate onau inclined aXiS and haring an unobstructed discharge end, means for introducing material to bc treated .into the feed end of the kiln. means for applying heat Within the other end of the kiln, whereb)v thc kiln is divided into drying, ealcining and burning zones. said kiln being of substantially uniform diauic1 ter throughoutv the drying and calciniug zones, and a Alrusto conical interior torni at the burning zone` whereby material passing through the kiln Will travel at a rclativel)` slow speed during its passage through thc drying and caleining zones and at an in` creased speed during its passage through the burning zone.

In testimony whereof, l have signed the foregoing specification.

SYLVESTER' S. MCGRAIH. 

